[#235] Concept checking fail for indexed_image

Subject: [#235] Concept checking fail for indexed_image
From: Mateusz Loskot (mateusz_at_[hidden])
Date: 2019-02-07 09:00:29

Hi.

https://github.com/boostorg/gil/issues/235

Are `memunit_*` functions are strict requirement of all image types?
I think it's not documented anywhere and "Read the code, Luke" needs
to be applied.

Meanwhile, if anyone (Christian?) has any hint to share, please do so.

Best regards,
-- 
Mateusz Loskot, http://mateusz.loskot.net